Tension brake device



April 15, 1952 c. L. PATTERSON Ix 2,592,595,

TENSION BRAKE DEVICE Filed March 22, 1948 2 SHEETSSHEET 2 I N V EN TOR. a? 60/f6/ [ea/70rd Pa/ferson A TTQRNE Y5 the full spool.

Patented Apr. 15, 1952 TENSION BRAKE DEVICE CarrelzLeonard Patterson, Danville,'Va., assignor to- Dan River Mills, Incorporated,"Danville, Va., .a corporation of Virginia .Application March 22, 1948, Serial No. 16,168

V .3 Claims. ;1

This invention relates to a' method and apparatus for tensioning. continuous materials. It relates specifically to the delivery,.under controlled tension, of yarns, i\abrics,.cords and thelike. from spools, or windings of anyosort.

In the method of producing high strength, w stretch yarns ithas-become an essential part of the art tostretchthe. material to approximately the breaking point before setting the peptized natural waxes and resins or. added bond- 10 ing agents. Such a method requires precision equipment in order that the yarn may be kept at a tension near the breaking point, where a slight increase or .slight fluctuation would cause rupture. One of the chief; sources of irregularity in tensioning yarns 'bythis method is in the delivery of the yarn from the supply spool.

It is the purpose of this inventionto describe a device which will permitdelilvery of the yarn from the spoolor bobbin under a uniform tension. It is a furtherpurposeof this invention to provide a device which will so tension the yarn as delivered from the :spool, that this device may be all that is neededto tension the yarn, and especially if itis a yarn of relatively-fine size and low tensile'strength.

The pulling tension necessary for unwinding yarn is comparatively slight when'thespool is full of yarn due to the'fact that the yarn exerts considerable leverage as it is pulled from the spool tangent to the'axis on-which the spool turns. However, asthe diameter of the yarn on the spool decreasesthe moment of this force is decreased until by the time the yarn has reached the last few layers on the spool, this leverage is so reduced that the pulling tension necessary to remove the yarn has-increased 100, per cent or more, depending, of course, on the diameter of With such a'variant existing, in order to remove the yarn from the spool without rupture, it is necessary to: have the tension very low when the spool is full so'thatthe increased natural tension at the end. of the delivery will not cause rupture.

A solution of this problem is to apply, by some auxiliary device, such tension-on the initial delivery of the yarn from the spoolthat the yarn is tensioned to near the breaking'polnt-and then gradually releasing the applied tension by this device so that the natural increase in :tension of delivery of the yarn from the spool is thereby compensated. In the normal delivery of yarn from a spool some retardant must be applied-in order to prevent the spool running freely at the time when the unwinding equipment is stopp d or its speed is decreased, .and causing what is known as back lash.

It is the gist of thisinvention.todescribea device which will achieve substantially .uniform 5 tensionirig of delivered yarn or cord. by applying friction braking as a retardant to the rotation of the spool as the yarnis delivered, thereby setting up tension in the deliveredyarn; and having this braking adjusted, constantly and automatically, as the natural tension on the yarn increases due .to the decreasingdiameter .of the yarn on the spool.

Other objects or" the invention are the provi- .:sionof a control .which'is unaffected by slight irregularities in the surface of the material yet unwound, and also the provision .of .a device which is automatically biased toward the windingfor close following thereof and which is further adjustable'for difierent directions of rotation. Otherobjects and features of the invention will be apparent in the following description and claims.

.Drawings accompany the specificationsand the various'views found therein may be described as:

.Figure 1,. afullview of. the apparatus in question showing. a spool imposition-to be unwound.

1 Figure 2, a view siiznilarto. Fleur-e1 inthe .ab- 381106 of the-spool.

Figure 3, a view on lines-3 of .Fi ure. 1. Figure 4,;a view on. line 44..of :FigureZ. Figure 5,: a modified constructionutilizing the basic-principle.

. Figure 6,;a view on .line 6-45 of Figure. 5. .In Figuresl vand-2alspool spindle 2c has a base disc .:22 whichrevolvesswith the spindle. The spindle is mounted in a bearingw24 which vis in turn mounted byai suitable bracket. 26 on a frame memberZB. The spindle 2!] projects through the bearing;24, and onthe Ieftasviewed in the drawings, there .is mounted. ajirictionfiisctii. The .disc. Zillis mounted to .rotate with the..-spindle 2t and has a .flat braking surface 32' lying. ina' plane -.which is normal tothe axis of thespindle 20. .A .spool 40 :slides on to spindle .20 and rotates therewith by reason of a stud! projecting axially from disc 22.

A combined brake and follower member .59 has .;:a projecting brakearm 52 and a projecting followerarmi l. Mounting eyes-56 and--58- are provided in axial alignment on the member 5%] for the purpose of supporting the member on a journal 60 on abracketfi I. The supporting eyesfifi and=58 are spaced apart a distancegreater than .the axial length of the=journalt0 anda supportingpin 62 passes through .these members. IIhe pin 62 is fixed in the journal 60 and at. one threaded end is provided a washer 64 and a nut 65 which serve as a suitable retainer for a spring 66 surrounding pin 62 and bearing at the other end against the eye 58. The spring 66 is compressed to urge the member 50 to the right as viewed in the drawings. Bracket BI is adjustably mounted on frame member 28 by reason of slots 68 in frame member 28 for reasons to be explained below.

On the end of arm 52 is a brake pad 10 which consists of a small shoe or disc which may be made of such materials as metal, plastics, cork, products of synthetic and natural latices, fibrous products, ligneous products, leathers, etc. Good results have been obtained by making this brake pad from metal of the porous type used in bearings. The disc 30 is preferably formed of material having the prerequisites of a satisfactory braking surface; that is, rigidity, durability, corrosion-resistance, smoothness, etc. Stainless steel is a satisfactory example. The brake pad in is preferably connected to the arm 52 by two free pins 72 and M, thus permitting flush contact of the braking shoe with the disc 30 at all times.

The arms 52 and 54 of the braking member 55 are preferably in approximately the same plane as shown in Figures 3 and 4. On the end of arm 54 is a follower wheel it which is intended to bear on the unwound thread of spool 35. The wheel "I6 has a radial position slightly outside of the brake shoe 70.

It will be apparent that the braking force on disc 50 will be directly proportional to the distance of the brake shoe from the axis of rotation. As viewed in Figure 3, the brake shoe has the greatest effect since it has the greatest moment arm around the spindle axis. As viewed in Figure 4, a shoe member ill would have the least braking effect. The distance of the shoe or pad 70 from the center of the braking disc is controlled by the follower wheel It which moves inward as the thread is unwound from the spool. Thus it will be seen that as the moment arm of the unwinding force decreases with the amount of residual thread on the spool, the effective moment arm of the brake also decreases. With this arrangement the unwinding tension may be practically uniform at all times. It is possible to deliver an entire spool of yarn tensions as near the breaking point as is commercially practical.

The counterpoising effect of a decreasing braking action together with a naturally increasing unwinding tension permits an equiponderate and uniform tension which is ideal in a yarn or cord stretching process.

In order to keep the follower roll bearing on the residual yarn on spool 40, the brake pad is mounted to swing on an are which is inside the center point of the disc 35 when rotation is in a counterclockwise direction as the parts are viewed in Figure 3. With this arrangement there is an inward pulling force on arm 52 at all times and follower roll will bear against the unwound yarn. Arm 54 is preferably formed of spring steel to absorb minor irregularities in the yarn such as uneven places, knots, etc. Thus these irregularities will not create abrupt changes in the position of brake pad it and consequent abrupt changes in tension.

If the direction of rotation of spool 30 is to be changed the bearing pressure may be suitably adjusted by shifting bracket BI on frame member 28 downward to the point that brake pad I0 lies outside-the center point of disc 30. Thus when disc 30 rotates clockwise as viewed in Figure the brake pad would be pulled inward to the center.

In Figure 5 a modified construction is shown in which a spool spindle I00 is mounted in a bracket Iill which also supports a stud I02 projecting parallel to the spindle. A spool supporting disc I03 serves as a rest for head I04 of a spool which is pinned thereto for simultaneous rotation by a pin I06. The back of the disc I03 is provided with a smooth braking surface.

On stud I02 a braking and follower member III? is pivotally mounted and urged to the right by a spring I12 adjustable by a thumb nut H4. On member H0 is a follower arm H6 and a braking arm II8. The follower has a roller I29 and the braking arm has a brake shoe or pad I22 adapted to bear against the braking surface of disc I03. A spring I25 pulls the follower arm I I6 against the residual thread on spool IM. The construction of the device in Figure 5 is simplified from that shown in Figure 1 but the operation is identical therewith.

It will be understood that the tensioning plan disclosed herein is not limited necessarily to the use with yarn or thread, but this can be used in any process where a compensating tension device is needed or an even tensionis desired, such as feeding fabric for lamination, delivering cloth for processing, unwinding wire under tension, or similar operation.

What I claim is:

1. In a device for effecting uniform tensionin of a continuous material'being pulled off a spool which includes a rotatable mounting for a spool, a friction plate mounted for rotation therewith, and a bifurcate member mounted on an axis adjacent the mounting with one arm positioned to follow the unwound material and the other brake arm positioned to apply axial pressure to said friction plate a radial distance from the axis of said plate proportioned to amount of material left on the spool, means effective to shift the relation of pressure application to the axis of the plate to a position wherein the brake arm is urged toward the center of the plate by the rotation of the plate which comprises a shiftable mounting for said bifurcate mounting movable in a direction toward and away from the axis of rotation of said friction plate, and means to lock said mounting in a predetermined position wherein for any particular direction of rotation of said plate, the point of pressure application is positioned where a directional movement component is toward the plane lying in the axis of the plate and the axis of the bifurcate member.

2. A device for effecting uniform tensioning of a continuous material being pulled off a spool which comprises a rotatable mounting for a spool, a friction plate mounted for rotation therewith, and a bifurcate member mounted adjacent the mounting with one arm positioned to follow the unwound material and the other arm adapted to apply axial pressure to said friction plate a radial distance from the axis of said plate proportional to the amount of material left on the spool, said follower arm being formed of resilient, spring material, and means mounting said bifurcate memher on an axis parallel to but movable toward and away from the axis of rotation of said friction plate, and means to lock said last mounting means to position said pressure application on said plate in a quadrant having directional components toward a plane intersecting said axes.

3. A device for effecting uniform tensioning of a continuous material being pulled off a spool which comprises a rotatable mounting for the spool, a friction plate mounted for rotation therewith, and a bifurcate member mounted adjacent the mounting with one first arm positioned to follow the unwound material, and with the second arm adapted to apply axial pressure to said friction plate a radial distance from the axis of said plate proportional to the amountof material left on the spool, said first arm being formed of resilient spring material and means mounting said bifurcate member on an axis parallel to the axis of rotation of said friction plate, said second arm positioning said pressure application on said plate in a quadrant having directional components toward a plane intersecting said axes.

CARREL LEONARD PATTERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,602,159 Joyce Oct. 5, 1926 1,676,797 Nyman July 10, 1928 w 1,884,183 Pearson Oct. 25, 1 932 2,103,042 Sachtleben Dec. 21, 1937 2,254,255 Zeruneith Sept. 2, 1941 

